Current Issues in the Anesthetic Treatment of the Patient

for Orthopedic Sugery

경희의료원마취통증의학과

R4 김영순

1. Peripheral Nerve Blocks

Resurgence in the popularity of regional anesthesia techniques– Perioperative pain relief

Current issues in regional anesthesia– Choice of technique (PNS vs. paresthesia)– Appropriate mA and nerve response to accept– Superficial stimulation– Choice for procedure below the elbow– Choice for postOP pain relief– Blocks in anesthetized patients

1. Peripheral Nerve Blocks

PNS is preffered– Clear endpoint– High success rate– Ability to minimize paresthesia– Long history of minimal significant complications

Success with a PNS – Knowledge of anatomy– Initial stimulating current 1 to 1.5 mA : not painful– “Fine-tune mode”

• When a twitch is obtained, decrease stimulating current– Injection of local anesthetic

• When the best twitch is obtained at the lowest mA possible (0.2 to 0.3 mA)

• 2 mL injection after negative aspiration• Loss of twitch confirms proximity of the needle to the nerves• The remainder is injected with intermittent aspiration

1. Peripheral Nerve Blocks

Controversy about the proper mA– In early days, 0.5 to 1.0 mA as endpoint– Decreased to 0.2 to 0.3 mA

• With the use of insulated needles and close attention to success rate

• Concerns about impaling the nerve– Block should not be performed with the Pt. asleep– Unusual resistance or significant pain on injection

• No strong evidence that 0.2 mA is associated with the needle being intraneural

– Choyce et al.– Blocks should not performed in adult patients during general ane

sthesia• Intraneural injection• Injection of the cervial spinal cord

1. Peripheral Nerve Blocks

Superficial stimulation– Locating nerves superficially on skin with a PNS

• Entry point is determined before a needle stick• The number of needle sticks is decreased• The anesthesiologist looks more adept

– Metal component of an ECG electrode– Example ; Brachial plexus

• In the axilla• ECG electrode is connected to the nerve stimulator with the c

urrent at approximately 5 mA• Twitches of the brachial plexus are sought as proximal in the

axilla• Area is marked and becomes the needle entry location site fo

r performing the block

1. Peripheral Nerve Blocks

Based on the site of surgery– Interscalene block

• Shoulder down to the midshaft of the humerus– Infraclavicular nerve block

• Elbow, forearm, and hand– Axillary block

• Ulnar side of the hand

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Fig. 1 Diagram of the infraclavicular block

1. Peripheral Nerve Blocks

Infraclavicular block (Fig. 1) – Instead of palpating for the axillary artery, superficial s

timulation can be used to locate the brachial plexus as proximal in the axilla as possible

– Advantage at this level • Musculocutaneous nerve is still part of the brachial plexus • No need for a separate block of the musculocutaneous nerve

in the coracobrachialis muscle

– Biceps twitch is not a reliable endpoint – Twitches in the hand or forearm should be used as th

e endpoint• Generated from the median, ulnar, or radial nerve

1. Peripheral Nerve Blocks

Lumbar plexus block– For lower extremity surgery– In the distribution of the femoral, obturator, and lateral femoral c

utaneous nerves– Fractured hip repair, femoral shaft surgery, and other anterior fem

ur surgery

Femoral and lateral femoral cutaneous nerve block– Femoral neck fractures necessitating cannulated pinning

Combined femoral and sciatic nerve block– Effective for procedures on the knee or distal to the knee

Femoral nerve block or fascia iliaca block– Postoperative pain relief after knee surgery

1. Peripheral Nerve Blocks

Fascia iliaca block (Fig. 2)– does not use the

nerve stimulator technique

– Between the femoral nerve and the lateral femoral cutaneous nerve

Fig.2. Diagram of the fascia iliaca block

2. Spine Surgery

Current issues– Understanding the degree of cervical spine pat

hology– Caring for patients undergoing prolonged surgi

cal procedure– Use of lung isolation technique– Loss of vision– The effect of NSAIDs on bone healing

Difficulty intubating patients with RA– Temporomandibular joint arthritis– Hypoplastic mandible– Overbite– Effects of RA on the cervical spine

• Atlantoaxial subluxation• Subaxial subluxation• Superior migration of the odontoid

Ankylosing spondylitis– Fused cervical spines fixed in a flexed position– Forced movement ; cervical cord damage– The head must be supported– Breathing in a rapid shallow pattern

2. Spine Surgery

Organized approach to the Pts. with cervical spine disease– Proper preOP evaluation

• Range of motion• Review of x-rays in flexion and extension• Appropriate use of intubation aides; flexible bronchoscope

Major spine surgery– Anterior procedure

• Thoracic exposure, lung isolation– Taking many hours– Major blood loss and fluid shifts– Perioperative considerations

• Controlling blood pressure• Monitoring spinal cord function• Treating blood loss• Positioning concerns

2. Spine Surgery

Lung isolation technique– Double-lumen tube or bron

chial blocker – Univent tube® (Fig.3)– Advantage

• Does not have to change the endotracheal tube between ant. and post. portions of the surgery

• Can be left in place if controlled ventilation is necessary in the postoperative period

– Drawback• External diameter is large

2. Spine Surgery

Fig.3 Diagram of technique using a double-lumen tube with bronchial blocker for lung isolation in open thoracic or thoracic procedures.

Prone position– Alteration in pulmonary function– Increases in venous pressure– Pressure and stretch on nerves– Visual loss

Postoperative vision loss– Combination of factors

• Perioperative anemia• Hypotension• Prolonged surgery• Resistance to blood flow

– Direct pressure on the eye • not seem to be the cause of the majority of cases of visual loss

2. Spine Surgery

Ischemic optic neuropathy– Common diagnosis in postOP visual loss– Decreases in ocular perfusion pressure(OPP)– Decreased blood supply to the optic nerve– Posterior ciliary arteries ; end arteries

• Placing the area at risk for ischemia as OPP is decreased

– OPP = MAP – IOP• Decreases in MAP or increases in IOP decrease OPP

– Prone position, especially in a slight head-down tilt• Edema and venous engorgement• Increasing IOP

– Etiology of vision loss is unclear

2. Spine Surgery

Nonspecific NSAIDs– Ketorolac ; interfere with bone fusion after spine surgery

• Avoid using ketorolac in this setting– Specific cyclooxygenase 2 inhibitors

• Recommendation for use ; necessitate further clarification

IntraOP monitoring of spinal cord function– Somatosensory evoked potentials

• Nitrous oxide-oxygen, opioid technique with an infusion of propofol and muscle relaxant

• Benzodiazepine ; avoided – Motor evoked potentials– Electromyograms

• Assess pedicle screw placement• Muscle relaxants must be discontinued early enough

– Wake-up test• Remember secure the endotracheal tube

2. Spine Surgery

Considerations before deciding to extubate the patient– Combined anterior-posterior spine procedures

• Can be prolonged

– Degree of swelling ; important– Significant facial swelling

• indication to leave the endotracheal tube in place

– Additional improtant factors• Hematocrit• Body temperature• Pulmonary function• Reversal of neuromuscular blockade

2. Spine Surgery

3. Anticoagulation and Orthopedic Patients

Major concerns– High incidence of deep vein thrombosis– Associated risk of fatal pulmonary embolus

Attempt to decrease the incidence– Anesthesiologist; neuraxial anesthetic– Surgeon; periOP thromboprophylaxis

• Warfarin or Dextran®

• LMWH and other antithrombotic agents– e.g., Fondaparinux, an anti-Xa medication

Spinal hematoma– US FDA to issue a warning

• Anticoagulants or antiplatelet medication in addition to LMWH• Epidural catheter removed at a time of therapeutic anticoagulation by t

he LMWH– Occurred muck less freauently in Europe

• Dosing interval, Dosage, Level of attention• More subtle onset of neurologic changes

– Not the excruciating back pain– Other anticoagulants or antiplatelet medications

• Should be avoided when LMWH is used– Appropriate timing

• Neuraxial anesthesia 10 to 12 hours after last dose of LMWH • First dose of LMWH in the postOP period

– Clopidogrel• Potent antiplatelet medication• A week before performing spinal anesthesia

3. Anticoagulation and Orthopedic Patients

The End